Fuel Gauge Issue?

[WReyno70]

Hi All,

My recently purchased S54's Fuel gauge is permanently indicating full although I know this is not the case. The needle is not stuck as it returns to Zero when the ignition is turned off, is there anyone who has had a similiar issue and managed to resolve it?


I have been told this can be the Fuel sender unit and pump which are replaceable - does anyone know how to diagnose if this is the problem? I dont want to replace it to find the issue remains.

Many thanks for any help or advice provided

Wayne

[Thesurveyor]

I had a problem with the gauge on my 2.8 whereby it would go no further than 2/3 full but would behave OK once it "caught up with itself". Totally cured by new sender but this is combined with the pump so it's more costly and involved than it might be. Also involves cutting a hole in the carpet behind the driver's seat.

[spurs fan in a coupe]

I have done a write up of how to do the fuel sender / pump unit replacement

https://zroadster.org/threads/remove-fu ... post-39429

I also have second hand (bit working at time of removal) fuel sender units for sale.

Cheers

[Southernboy]

The only way you will resolve the problem is to remove the fuel pump / sender unit from the tank. Once removed, you will see the little plastic float on the end of a wire arm. As the fuel level changes, it has a contact which traverses a potentiometer coil which changes the electrical current delivered to the fuel gauge. Often what is required is the contact area to be cleaned. If however the coil is damaged / broken it will mean replacing the pump / sender unit.
Removing it is done via a "cut-out" in the fitted carpet behind the driver seat. There are several posts on the forum describing the process. First thing to do is to run the car until it is practically out of fuel - somewhat tricky with a errant fuel gauge indication in your case. The reason for that is to get the fuel level below the aperture created when removing the pump / sender and to avoid fuel pouring into the car and soaking into the carpets. Again, you can refer to Andy - Spurs fan who will be able to describe the removal / fitting process to you exactly.

[Inferno]

when you open your fuel tank cap to refill fuel do you hear a loud air escaping noise?

[WReyno70]

The only way you will resolve the problem is to remove the fuel pump / sender unit from the tank. Once removed, you will see the little plastic float on the end of a wire arm. As the fuel level changes, it has a contact which traverses a potentiometer coil which changes the electrical current delivered to the fuel gauge. Often what is required is the contact area to be cleaned. If however the coil is damaged / broken it will mean replacing the pump / sender unit.
Removing it is done via a "cut-out" in the fitted carpet behind the driver seat. There are several posts on the forum describing the process. First thing to do is to run the car until it is practically out of fuel - somewhat tricky with a errant fuel gauge indication in your case. The reason for that is to get the fuel level below the aperture created when removing the pump / sender and to avoid fuel pouring into the car and soaking into the carpets. Again, you can refer to Andy - Spurs fan who will be able to describe the removal / fitting process to you exactly.

Thank you very much for the information and guidance - probably worth looking at cleaning the contacts before a full swap.

Many thanks